The effect of vanadium and grain refiner additions on the nucleation of secondary phases in 1XXX Al alloys
High purity Al-0.3 wt% Fe-0.1 wt% Si alloys with different Si, V and grain refiner contents were melt spun to produce microstructures of submicron secondary phases entrained in a higher melting point Al matrix. On reheating, a dispersion of eutectic liquid droplets forms that represents an exaggerated version of the liquid puddles that solidify punched-off between Al dendrite arms during conventional casting. The subsequent resolidification of the droplets, analyzed using differential scanning calorimetry (DSC), allows the nucleation-controlled aspects of secondary phase selection to be studied. The droplets solidify as the metastable FeAl{sub m} phase in ribbons containing {approx{underscore}equal}500 ppm V or {approx{underscore}equal}100 ppm V plus Al-Ti-B, Al-Ti-C or Al-B grain refiner. This phase contributes to the fir-tree surface defect in commercial sheet products. this work suggests that the combination of V and Al-Ti-B promotes FeAl{sub m} in commercial ingots, and confirms that solidification rate and bulk Si content also influence phase content.
- Research Organization:
- Univ. of Oxford (GB)
- OSTI ID:
- 20006424
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 17 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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